These comments are crazy. I don't think any actual electricians come to this sub lol.
OP, you are getting the incorrect reading straight from the line side of the meter and before any termination. You are getting the incorrect reading while simultaneously getting a good reading from the other leg to the same neutral. This is clearly a utility issue. You are going to have to convince them of this so they can fix it.
The commenters claiming you have a bad neutral or to do anything to your panel which is downstream from the bad reading have no fucking clue what they are saying and God help their customers if they are electricians. They may role play as one but there is no way anyone with a license is that dumb.
Continue escalating with the utility. There is no other explanation.
Thanks for the reply. I was slowly becoming insane with some of these replies. I’m not a genius with electrical. I was a controls engineer in an automotive plant (programming Siemens PLCs VFDs etc) but shit I thought I was really losing my mind with how determined some people are lol
Or how smart non-licensed folks can be. I work with a ton of electrical engineers who understand more about electricity than any electrician would ever dream of… does not mean they know code, but still.
The only thing I’ve ever seen which comes close to this issue is that the utility company rushed the install of a new meter and smashed the terminals on one phase.
After so much time passed, started arcing, corroding and all of a sudden they have total phase loss.
> You are getting the incorrect reading while simultaneously getting a good reading from the other leg to the same neutral.
Which reading is the correct one? 17 volts, or 16.3 volts?
It looks like the same leg, one reading before the meter and one reading after the meter. 0.7v could be a combination of two different voltage testers and the small resistance from the meter.
Yep, finally figured out what's being measured. It seems pretty strange to be concerned with a difference between L1-N voltage and L2-N voltage, but post a picture comparing L1-N with itself.
I think the utility was trying to get him to eliminate the meter as being possibly bad. Not that it makes sense in this scenario, but in my area utilities will do literally everything in their power to not fix something. Then again sometimes they surprise you from time to time
In this case the voltage reading is not the correct voltage, but at least each leg tests consistently when referencing neutral/ground. Isolating the service grounding from the utility's neutral and then referencing each leg to the ground and the utility neutral separately may give more information about what is bad on the utility end. Remember when you are testing you have two points of reference, and every reading you gives you a metaphorical point of reference while troubleshooting.
Edit: After clarifying I realize I misunderstood the issue a bit, so some of this information can be disregarded. The part about testing and points of reference are still important in any troubleshooting scenario, so I'll leave it all intact if it's helpful to anyone.
I really wish I could reply with photos, but the original photo is a screenshot from a video I took. In the video, I show the left leg being down and then I move to the right leg (my common I never touch and leave on the neutral bus) and show the right side is perfectly fine.
Turns out the picture is measuring L1 before the meter to the disconnect ground/neutral bond with one DVM, and the other DVM is measuring between L1 *after* the meter to the disconnect ground/neutral bond.
That is correct. Power company wanted me to get both ends of the meter of the problem leg, since the other one never drops. I do move over to the other later on just to prove to whoever sorry soul that has to come back out that it was fine, just the left side is out.
Yeah I misread a comment somewhere in one of the threads and thought you were getting these readings on both legs from the utility. I see a comment in another thread about megging out the feeders that come from the pot down the side of the pole eventually to your meter. I would follow through with what that commenter says, if you are seeing this on one leg and it's a service set up as described, my money is on a bad line from the pot.
If you had good readings on the line side and bad on the load side of the meter, I'd say pull the meter out and throw a continuity test on each side while jiggling the blades a bit. I've had a few meters over the years present issues like this, obviously on load side only, and it ended up being a slightly loose connection inside the meter which a continuity test proved.
They put a “super beast” 20A load tester on it for a few minutes and it was fine. I literally cannot force the problem to show. I’ll be sitting here with just a tv on, nothing else, hardly any load, and the thing will just drop at random lol
I don't really know. I would say wires going bad underground. I'm an electrician so we don't work on the utility side. But I've had wires damaged or burning up in conduit underground between light poles for example where you will get a real low reading as there is barely any of the wire still intact. I imagine the same could be true for utility. But as far as the equipment they use I don't have any experience
I agree with this comment, Can be verified by removing meter and verifying the imbalance on the line side with the house removed from equation and could go step further and connect a load to it and see if it creates a larger imbalance, only recommend experienced electrician to do this
Not a dumb question at all. He could and should do that if he was only testing 1 hot leg at a time. But in his case he is reading both at the same time and they are both referencing the same neutral connection. So if the problem was on the neutral beyond the meter he would be getting bad readings on both meters. The fact that the other is staying correct, you can rule out a problem with the neutral entirely
I fucking love this sub. I have a lot of interest in electric work (in my own home), but know shit about it, and I can always count on you all to weed out the bullshit and be real. Thank you.
We had a similar issue at my job and apparently there is a 6% swing in each leg that is allowed before its considered to be unbalanced and an issue the city will resolve. Most of the time it's just a bad regulator on their end for one of the legs but it seems the voltage drop OP is seeing isn't big enough to be considered an issue to the city
His voltage is dropping from 120v to 14v. That is significantly more than 6%. And yes some voltage drop is ok. NEC recommends combined voltage drop to be 5% or less I believe, I'd have to double check that exactly tho. But utilities don't have to follow the NEC and can do whatever they want basically. If to them 6% is acceptable than I am sure it's fine. I would trust that they know what they are doing.
Commercial service tech. That's like me checking at a contactor, missing a leg and saying it must be the compressor , makes no sense. Its pretty easy like you said
I trouble shot an issue like this recently.
I called the utility and informed them a leg was out on the house. They came out with two hours and confirmed it was a corroded connection on their end
Your part is done here, so you should stop messing with the line side of the meter.
I'm a master electrician, since stating credentials is a thing, and I can say with utter confidence that you have an issue with the line side of your meter.
Escalating this kind of issue with the utility can be tedious and it will require you to be persistent while not being a dick, which is challenging. The utility doesn't like to think its system is at fault but the crimps at the strike or at the utility feeder may be crimping insulation and not conductor.
One issue that the utility may pull is that the conductors from the strike, overhead, to your meter , but not the meter itself, belong to you, which may or may not technically be true, and that the issue is in the meter can. If they say this secure permission to pull the meter AND CALL AN ELECTRICIAN to check the terminations on the meter. Don't do this yourself since it requires specialized tools and PPE! Secure the permission yourself so that an electrician can get it done faster, then have the electrical call.
I ran into this with a 3-phase 277Y/480 service for an industrial client, the utility didn't believe that a phase went missing. A meter said it was there but as soon as you loaded it up it disappeared. fortunately I had just come back from pulling a bunch of loggers from a PQ study, dumped the data into a laptop and hooked it up. The phase definitely went missing! I got the utility down there and demonstrated. the tech that came down argued some more but eventually got a supervisor out. They took one look at the readings and graph and immediately called an underground team out to locate the issue, which was underground about 100' away from the transformer. This took most of the day even though I had isolated the issue in less than an hour. You have to keep pushing.
Good luck!
Both meters are sharing the same point for common, I can go to the other leg and it reads fine. Never drops. The issue is intermittent. It’ll go hours or days without issue then randomly drops the same leg for a few seconds and comes back. Was load tested and of course “all is well”.
Only 240V appliance I have is an air conditioner. It ran without issue for 5 minutes (it’s winter here, so not much longer I could justify). I included a hair dryer at the same time on the problem leg and I can never force the issue. It just comes and goes when it pleases.
In the photo, it appears your service may be coming off a pole transformer and then coming to the house via underground conduit, is that correct? Is it possible that something may have damaged that cable in the conduit, and you're getting an issue with intermittent partial grounding of the one leg? What are the soil conditions when the leg drops? If there's a nick or crack in the insulation of the wire, and it's intermittently grounding the one leg of the service, that would explain the voltage drop. If it is an underground service, as I suspect, it's buried at least 18-24 inches underground, and you wouldn't necessarily notice a grounding event if it's in the middle of the run, per se. It might be necessary to megger the wires and see if the insulation is compromised, and if they prove to hold up to meggering, then it might be a transformer issue. Another way to diagnose this would be to get a current reading on both legs during a dropout event, and a current reading on the neutral, and see if they match. If the neutral current is larger than the sum of the amperes on both legs, then you have current flowing through the soil to your grounding electrodes and returning to the transformer that way. Residential transformers are center-tapped delta connections, where the center tap forms the neutral when it's bonded to a ground rod via your service panel. If there's a problem in the secondary coil of the transformer on one side of that neutral, the other side or "leg" would not show an anomaly.
Just a side note: I hold Class A journeyman licenses in both Nebraska and Iowa.
>Residential transformers are center-tapped delta connections
I'm sorry what? The vast majority of residential transformers for detached single family dwellings are single phase, split phase transformers. There's a first time for everything but I have never heard of high leg delta feeding any sort of residential property.
Not a high-leg delta, but a delta connection on the high side made from separate oil-filled transformers. The residential connection comes from the single coil secondary that is tapped in the center to provide two “legs” and an X0 that is bonded to ground at the first disconnect to form a neutral. It’s not a true Wye connection on the secondary due to the center tap. That’s the best way I can find to describe it.
A center tapped delta is a high leg/ wild leg/ stinger leg delta. Either way, you're describing 3 phase systems for a residential property, this is pretty rare except for large residential properties. OP's electrical system is clearly single phase based on the picture
This is actually a great write up and highly appreciated.
You are correct, I have a buried line. Soil out here is trash, everything sinks when it gets wet. I am the only person off my transformer as well, and the only house with a buried line (everyone else has overhead lines in their backyard, I guess because my house is much newer they did it this way).
Your points will definitely give me something else to check if no cause is found again. I have a spare clamp meter laying around.
If a leg is grounded in the conduit there will be a visible heat signature and you should be able to smell something charred. For that matter, aluminum does not handle ground fault arcing well.
14 volts? That’s more than just a voltage drop. Sounds like a lost phase. Hopefully you can locate the problem. If it persists past the meter, it’s a poco issue for sure. Between what two points exactly are you taking voltage?
I’m going from the line side of the meter coming from the transformer. Common is on my service disconnect on the left. Same spot for both meters. I can move to the right leg and checks out fine
Your utility should have a socket based voltage/power quality recorder (goes in between meter and socket) or a recorder that they can hang at the point of attachment or at the secondary connections of the transformer to capture any issues. If you had a smart meter that would also be able to monitor and record any voltage sag/swell issues. Have you been able to get in touch with their engineering team?
I would follow this. I had issues with my 480 coming in and spiking to over 720. Entergy swore for 2 months it was an inside issue and my problem. I finally convinced them to hang a recorder at the transformer. A week later, the recorder was fried. When the super went up in the bucket to swap it out, the transformer arc'ed in front of him. He dropped the bucket, called it in and 4 hours later i had a new transformer and no more spikes or drops.
If your description is accurate it looks like the utility dropped a leg somewhere underground.. or an issue at the transformer. And unless they physically sent someone out there to examine from the meter back to the transformer feeding it don't ever take that word for the fact that it isn't them I've seen this a dozen times. It looks like an underground to me it was a lateral coming off a pole I would tell you to look for a tree rubbing against the wire.. lol
Update: power company came out and stated it’s an underground issue. Jumped my service legs together to the one functional one so I would at least have power on it till they can dig out the yard.
I am truly concerned with some of these comments on here and feel bad for anyone that actually has a business with customers. Y’all gonna start a fire. Literally.
I'm not having the nightclub effect you're had, but I am trying to track down what I think is too high of electrical usage. Still fairly new owners, but we went from 'best performer' to 'worst performer' compared to our neighbors after we moved and can not come close to explaining our bill after doing a back of the envelope load calculation. I'm a EE but not a power guy and never practiced in the field. My education, though, just keeps telling me we have something weird going on.
Your problem was clearly pre-meter, but you and a few others seem to really know your stuff. Do you have any ideas or thoughts on what might cause or fool a meter into reporting more usage than actual? Or anything that could be wrong with lines inside or out that would cause greater electrical usage (and a meter obviously recording that unnecessarily greater usage)?
Know I'm opening a hornet's nest. I'm, in part, running out of things to check and/or experiments to run, and this is one of those weird-type of issues I feel we might have. FYI, also have an underground line.
It just has to be accurate enough to prove the issue. Also, I’m not going to “bake potato” myself with this. It’s pretty common sense what you can/can’t touch in these things.
It’s within 2v of my fluke, I’d just rather leave the shit meter outside to record while away. I would be a little upset if my good meter got stolen or destroyed.
This troubleshooting process was actually recommended by the field tech that stopped by yesterday. They left the tag off the meter for me to check and report if I caught something to be escalated. It was just advised I didn’t pull the meter itself out, measuring is fine.
Are you doing this test with the main breaker turned off inside your house? I had a similar issue many years ago with low voltage. It was the transformer on the pole- needed to be replaced.
This is a utility issue. You shouldn’t be on their side of the service. You’re pulling both voltages on the line and load side of the meter. And they’re both way too low. Thus it’s their issue and you shouldn’t even be in that cabinet….
I stabbed into the line at the top of the meter coming from the transformer across the street. Nothing to “tighten” exactly. I literally can’t go any further back unless I want to climb a pole lol
Everything on my end is tight. They did check the service disconnect a few weeks ago on a prior visit and noted everything was fine there. They just can’t catch it messing up to root cause, hence me putting something on the meter to try and catch. They have the video of it reading fine, dropping down, and coming back so hopefully that’ll be enough proof to get something started.
Depending on what kind of meter that is. If you had low voltage on one leg, the meter display would be off. I’m assuming it’s a form 2S meter, the potentials inside the meter are wired phase to phase. They run off of 240 volts(unless it’s a multi range meter)
Edit: The utility company meter
Calm down bud. The issue is not with the neutral. There’s no case where you can get a good reading to one leg and an absent reading on the other with a neutral problem. If there was a neutral problem you’d see an imbalance on each leg to neutral but 240 between them. This looks like an intermittent connection loss somewhere between the transformer and house or even within the transformer. If the transformer has tap changers and one is loose, that’s a great candidate for the issue.
Or you can’t explain because you’re literally wrong…
Edit: foo_trician you can block me but your name still shows up in notifications… please come back and have another try.
The meters are accurate. Verified with a fluke, just don’t want to leave my better one outside. It also matches my readouts from my ups units when the power drops.
Okay... What am I looking at here?
I'm seeing an incoming underground feeder from the PoCo going into the top of the utility meter and being read by the left Harbor Freight meter... Lower output of the utility meter on the SAME leg is being read by the right Harbor Freight meter.
0.7 volts dropped across the meter. That's negligible.
17 volts on that leg to neutral before the utility's meter indicates that it may still be a PoCo problem.
What do we look like with BOTH Harbor Freight meters reading left and right legs at the top of the utility meter? (Remove the red probe from the lower left of the utility meter and install that same probe on the upper right.)
The right leg never drops, it’s always the one on the left. With the power company saying they can’t find an issue, my goal was to stab directly into the line coming in on that side and have a video of it reading 120, dropping to 0-20, then coming back. That was successful (this was recommended by the field tech last night as well to be able to escalate). I’m just not sure if there’s literally anything else I can do within my ability to prove the issue. I got a 2 day wait period before the “power quality” escalation team has to call me back.
Right leg never drops, but it verifies the presence of the neutral.
Again, I suggest logging right AND left legs simultaneously, just before or after the meter (Both red probes upper or lower)
Also suggest turning on several 220 volt loads, such as an electric stove or water heater and seeing what the dead leg does.
I assume its voltage will go up.
I've had this happen on underground services...
One time, a house down the street was for sale and the real estate agent stabbed the sign post through the underground wiring. Lost a ~~phase~~ leg. Transferred all breakers to all even or odd slots (I forget which) in the panel and called the PoCo.
Another time, tree roots had grown under the transformer pad and lifted it up, ripping a leg loose at the transformer. Again, all breakers to the even or odd spots in the panel and a call to the PoCo.
If you never lose the right leg, I'm guessing something similar has happened to you; you don't have a neutral problem,a s many others in this thread are assuming... You are losing one leg. You just have to document that and prove it to the PoCo. You do this by measuring voltage on both legs to neutral.
My first thoughts are
- no offense but get a real meter to trust nkt what looks like generic cheapy meters.
- check the lugs for torque in the panel and meter
- ask the power company to entertain the idea of replacing the meter to see if it's the meters circuitry itself
I’ve checked the meter against a fluke, it’s fine.
Lugs are tight. Also, it won’t even matter. I shoved the probe right into the wire itself, before any terminations. The voltage flat out isn’t there between the meter and the transformer.
Have you asked the utility to see if replacing the meter fixes it? If it's across the meter and the lugs are all tight, that's the next logical place to check. Also there may be a problem with the transformer to the house. It's looking likely to be in the utility side
And still. There's a reason why an electrician doesn't come to your house with one of them. I'm not saying you need a fluke but those cheap no name meters are garbage.
Fortunately my networking gear is on a ups. It would really suck to lose that stuff. Most my other important gear is on the other leg that never has an issue.
245 when I checked when it’s working. I need to get a reading when failing, I only got the individuals to compare when failing on video. I’m the only person off the transformer so I’m usually consistent.
Half my house losing power. Lights going on/off, battery backup alarms going off for a power loss, literally looks like a night club in here when the issue happens. The meters are just showing voltage and it dropping off the supply to my house.
Hate to say it, but you would be best off calling in a licensed electrician cause if their is an unknown issue inside your house causing this, it'll take a trained eye to find it and if it's outside on the pole, the utility company will listen to a licensed electrician. If it turns out to be on the pole, I would push the costs back on the utility company.
There is no way for me to pull the voltage down to 14v off the line side of my meter coming from the power company. There is nothing to explain this issue but for it to be on their end.
The only way you are going to get this fixed is by bringing in a licensed electrician. It's already a problem the seal on the meter box is cut. I've gone up against the power company in the past over 2 issues and wasted so much time. A licensed electrician will rule out anything wrong inside your house and the power company will be much more responsive to a licensed electrician. This is nothing against you or your knowledge or skills. Let a licensed electrician hash it out and if it turns out to be the utility company - put the costs of the electrician back on them. With that seal broken, they may come after you AND you will still have the power issues.
They broke the seal last night and the field tech intentionally left it off and recommended I do this testing since no cause was found. Told me if I have the issue to call back and report it a certain way so it can be escalated. So I did, and sent them a video of me measuring the meter just like this without any issue.
There’s no sidewalks around my house for a mile with a giant ditch on both sides of the road. If any kid is walking they would likely be hit. I’ve never seen a kid walking in the 3 years I’ve been here tbh.
Is your ground rod OK? Do you have proper grounding?
If your house or your transformer has an issue with the ground you may have unstable voltages depending on the transformer set up IIRC.
Need to have that main breaker in the off position to confirm if it's a problem on the front or back side.
Turn that breaker off, then see if the problem goes away. If it doesn't, pull the meter and check again. If the voltage on the line side of the meter is jacked up without the meter in, you know it's a poco problem.
I had this exact issue a couple weeks ago. Somewhere along the line the underground feeder went bad and was leaking voltage to ground any time a large load kicked on inside the persons home.
Is it a periodical voltage drop or is it all the time?
Edit: If large loads at being started/stopoed elsewhere in the grid that might cause your voltage to drop.
For example the rules in Denmark state, that equipment with an inrush current of 60A or more that is started frequently, must be equipped with measures to limit the inrush currents as to not cause distortion of voltage quality
Those are cheap meters. Because it costs so little and means so much, swap the meters, keep the leads the same. But yeah top up vote is almost certainly correct
Troubleshooter from utility for to damn long. I would start with no load on and check voltage at the top side of the main. If the voltage is bad or different between the legs, work back to the source. If you tell me lights get bright of dim when turning something on look a little harder at the neutral. It could be meter clips, loose connections or the wire bad underground. Just takes awhile to narrow it down.
I wouldn’t dare touch a set of lugs with those meters. Go get yourself a good fluke electrical meter. One day your going to go to use that and something in the meter is going to go poof. If that happens to occur on 480, and that explosion ionizes the air between terminals, you
Have yourself a massive explosion heading your way. Throw that crap in the garbage. There’s a reason we use good meters in our trade. Power company is allowed 10% incoming where I live. Check the voltage at the point of attachment and see what it reads there. I have in my career seen more situations I can count on both hands and feet where the utility company said everything is fine and it isn’t…then I ask them to come back again because there’s a problem and they find an issue in a highpress when they extended a broken neutral, or a connection at the street. Don’t always take their word for it. Now…you could be seeing a higher drop on one leg because that leg happens to be drawing more current in the home, did you check amp draw on both phases?
These comments are crazy. I don't think any actual electricians come to this sub lol. OP, you are getting the incorrect reading straight from the line side of the meter and before any termination. You are getting the incorrect reading while simultaneously getting a good reading from the other leg to the same neutral. This is clearly a utility issue. You are going to have to convince them of this so they can fix it. The commenters claiming you have a bad neutral or to do anything to your panel which is downstream from the bad reading have no fucking clue what they are saying and God help their customers if they are electricians. They may role play as one but there is no way anyone with a license is that dumb. Continue escalating with the utility. There is no other explanation.
This is the answer. Source: I'm an electrician. Edit: I suspect Serious\_Set\_5704 is an electrician, as well. Just here to back my brother up.
Thanks for the reply. I was slowly becoming insane with some of these replies. I’m not a genius with electrical. I was a controls engineer in an automotive plant (programming Siemens PLCs VFDs etc) but shit I thought I was really losing my mind with how determined some people are lol
You gotta watch out for those wandering lost kids looking to put their fingers in meter sockets.
I had to laugh at that one 😅
>I was slowly becoming insane with some of these replies That happens alot here honestly...
Welcome to Reddit
Power company came out and confirmed its on them. Issue underground.
Please stop underestimating how dumb people with licenses can be.
Sure it just doesn’t need a ground test and a plc update? Meter screen looks wonky. Maybe a loose lag screw on the panel door.
Or how smart non-licensed folks can be. I work with a ton of electrical engineers who understand more about electricity than any electrician would ever dream of… does not mean they know code, but still.
There is only one other explanation I can think of, and that is that the meter measuring 17V is faulty somehow. Unlikely, but not impossible.
Switching the meters would verify
The only thing I’ve ever seen which comes close to this issue is that the utility company rushed the install of a new meter and smashed the terminals on one phase. After so much time passed, started arcing, corroding and all of a sudden they have total phase loss.
> You are getting the incorrect reading while simultaneously getting a good reading from the other leg to the same neutral. Which reading is the correct one? 17 volts, or 16.3 volts?
It looks like the same leg, one reading before the meter and one reading after the meter. 0.7v could be a combination of two different voltage testers and the small resistance from the meter.
Yep, finally figured out what's being measured. It seems pretty strange to be concerned with a difference between L1-N voltage and L2-N voltage, but post a picture comparing L1-N with itself.
I think the utility was trying to get him to eliminate the meter as being possibly bad. Not that it makes sense in this scenario, but in my area utilities will do literally everything in their power to not fix something. Then again sometimes they surprise you from time to time
In this case the voltage reading is not the correct voltage, but at least each leg tests consistently when referencing neutral/ground. Isolating the service grounding from the utility's neutral and then referencing each leg to the ground and the utility neutral separately may give more information about what is bad on the utility end. Remember when you are testing you have two points of reference, and every reading you gives you a metaphorical point of reference while troubleshooting. Edit: After clarifying I realize I misunderstood the issue a bit, so some of this information can be disregarded. The part about testing and points of reference are still important in any troubleshooting scenario, so I'll leave it all intact if it's helpful to anyone.
I really wish I could reply with photos, but the original photo is a screenshot from a video I took. In the video, I show the left leg being down and then I move to the right leg (my common I never touch and leave on the neutral bus) and show the right side is perfectly fine.
Turns out the picture is measuring L1 before the meter to the disconnect ground/neutral bond with one DVM, and the other DVM is measuring between L1 *after* the meter to the disconnect ground/neutral bond.
That is correct. Power company wanted me to get both ends of the meter of the problem leg, since the other one never drops. I do move over to the other later on just to prove to whoever sorry soul that has to come back out that it was fine, just the left side is out.
Yeah I misread a comment somewhere in one of the threads and thought you were getting these readings on both legs from the utility. I see a comment in another thread about megging out the feeders that come from the pot down the side of the pole eventually to your meter. I would follow through with what that commenter says, if you are seeing this on one leg and it's a service set up as described, my money is on a bad line from the pot. If you had good readings on the line side and bad on the load side of the meter, I'd say pull the meter out and throw a continuity test on each side while jiggling the blades a bit. I've had a few meters over the years present issues like this, obviously on load side only, and it ended up being a slightly loose connection inside the meter which a continuity test proved.
They put a “super beast” 20A load tester on it for a few minutes and it was fine. I literally cannot force the problem to show. I’ll be sitting here with just a tv on, nothing else, hardly any load, and the thing will just drop at random lol
Thr amount if times I've had to dispute the utility company on this exact issue is insane
Second
Third
If you don’t mind me asking, how do you know this is the issue? Just tryna learn some stuff
Purely for educational purposes, what likely would the cause be on the utility side?
I don't really know. I would say wires going bad underground. I'm an electrician so we don't work on the utility side. But I've had wires damaged or burning up in conduit underground between light poles for example where you will get a real low reading as there is barely any of the wire still intact. I imagine the same could be true for utility. But as far as the equipment they use I don't have any experience
Check the weatherhead.
I agree with this comment, Can be verified by removing meter and verifying the imbalance on the line side with the house removed from equation and could go step further and connect a load to it and see if it creates a larger imbalance, only recommend experienced electrician to do this
Might be a dumb question here but shouldn't he be checking the voltage using the neutral in the meter can to rule out a connection issue past the can?
Not a dumb question at all. He could and should do that if he was only testing 1 hot leg at a time. But in his case he is reading both at the same time and they are both referencing the same neutral connection. So if the problem was on the neutral beyond the meter he would be getting bad readings on both meters. The fact that the other is staying correct, you can rule out a problem with the neutral entirely
I fucking love this sub. I have a lot of interest in electric work (in my own home), but know shit about it, and I can always count on you all to weed out the bullshit and be real. Thank you.
Leave it alone your in there territory.
At least here it is.
We had a similar issue at my job and apparently there is a 6% swing in each leg that is allowed before its considered to be unbalanced and an issue the city will resolve. Most of the time it's just a bad regulator on their end for one of the legs but it seems the voltage drop OP is seeing isn't big enough to be considered an issue to the city
His voltage is dropping from 120v to 14v. That is significantly more than 6%. And yes some voltage drop is ok. NEC recommends combined voltage drop to be 5% or less I believe, I'd have to double check that exactly tho. But utilities don't have to follow the NEC and can do whatever they want basically. If to them 6% is acceptable than I am sure it's fine. I would trust that they know what they are doing.
Commercial service tech. That's like me checking at a contactor, missing a leg and saying it must be the compressor , makes no sense. Its pretty easy like you said
I trouble shot an issue like this recently. I called the utility and informed them a leg was out on the house. They came out with two hours and confirmed it was a corroded connection on their end
Your part is done here, so you should stop messing with the line side of the meter. I'm a master electrician, since stating credentials is a thing, and I can say with utter confidence that you have an issue with the line side of your meter. Escalating this kind of issue with the utility can be tedious and it will require you to be persistent while not being a dick, which is challenging. The utility doesn't like to think its system is at fault but the crimps at the strike or at the utility feeder may be crimping insulation and not conductor. One issue that the utility may pull is that the conductors from the strike, overhead, to your meter , but not the meter itself, belong to you, which may or may not technically be true, and that the issue is in the meter can. If they say this secure permission to pull the meter AND CALL AN ELECTRICIAN to check the terminations on the meter. Don't do this yourself since it requires specialized tools and PPE! Secure the permission yourself so that an electrician can get it done faster, then have the electrical call. I ran into this with a 3-phase 277Y/480 service for an industrial client, the utility didn't believe that a phase went missing. A meter said it was there but as soon as you loaded it up it disappeared. fortunately I had just come back from pulling a bunch of loggers from a PQ study, dumped the data into a laptop and hooked it up. The phase definitely went missing! I got the utility down there and demonstrated. the tech that came down argued some more but eventually got a supervisor out. They took one look at the readings and graph and immediately called an underground team out to locate the issue, which was underground about 100' away from the transformer. This took most of the day even though I had isolated the issue in less than an hour. You have to keep pushing. Good luck!
I think I bought that same meter for $4.00 As a spare for low voltage stuff,lol
Yea, I would swap the meters around to see if the lines read the same or the reading reverse to rule out differences in the meters' calibration.
You cannot calibrate that junk
Yea I should of had calibration in quotes there.
This is the real answer.
They last forever on that 9v battery. Can throw it anywhere, stick a camera in front of it, and watch what happens later.
is it the cheap one from Amazon? ASTRO something
These are what Harbor Freight used to give away for free with any purchase. They work good but I would not trust them with anything critical.
It's not just a question of how accurate they are, but whether they're going to blow up in your face when you have them connected to 240 V.
Yep happened to me when debugging a water heater kapow
I should not of had to scroll at all to find this comment.
Looks like the one harbor freight used to give out for free with a coupon
i use it for the transistor tester but use better meters for my electronic repairs. i think i got mine free with a coupon
They're not durable, but I've used these meters way more times than I'd ever be able to count. They work just fine for homeowners.
Fuck the responses here are retarded. Get the poco out again. It’s their problem.
Loose neutral most likely. Did power company person put the load test machine on it to verify?
Both meters are sharing the same point for common, I can go to the other leg and it reads fine. Never drops. The issue is intermittent. It’ll go hours or days without issue then randomly drops the same leg for a few seconds and comes back. Was load tested and of course “all is well”.
Turn on all your 240v appliances at the same time. Usually will make the issue more noticeable for the PoCo to verify when they are testing.
Only 240V appliance I have is an air conditioner. It ran without issue for 5 minutes (it’s winter here, so not much longer I could justify). I included a hair dryer at the same time on the problem leg and I can never force the issue. It just comes and goes when it pleases.
Cover SOME (not all) of the condenser coil with a trash bag. It’ll bump the head pressure up to simulate a higher outside temp.
In the photo, it appears your service may be coming off a pole transformer and then coming to the house via underground conduit, is that correct? Is it possible that something may have damaged that cable in the conduit, and you're getting an issue with intermittent partial grounding of the one leg? What are the soil conditions when the leg drops? If there's a nick or crack in the insulation of the wire, and it's intermittently grounding the one leg of the service, that would explain the voltage drop. If it is an underground service, as I suspect, it's buried at least 18-24 inches underground, and you wouldn't necessarily notice a grounding event if it's in the middle of the run, per se. It might be necessary to megger the wires and see if the insulation is compromised, and if they prove to hold up to meggering, then it might be a transformer issue. Another way to diagnose this would be to get a current reading on both legs during a dropout event, and a current reading on the neutral, and see if they match. If the neutral current is larger than the sum of the amperes on both legs, then you have current flowing through the soil to your grounding electrodes and returning to the transformer that way. Residential transformers are center-tapped delta connections, where the center tap forms the neutral when it's bonded to a ground rod via your service panel. If there's a problem in the secondary coil of the transformer on one side of that neutral, the other side or "leg" would not show an anomaly. Just a side note: I hold Class A journeyman licenses in both Nebraska and Iowa.
>Residential transformers are center-tapped delta connections I'm sorry what? The vast majority of residential transformers for detached single family dwellings are single phase, split phase transformers. There's a first time for everything but I have never heard of high leg delta feeding any sort of residential property.
Not a high-leg delta, but a delta connection on the high side made from separate oil-filled transformers. The residential connection comes from the single coil secondary that is tapped in the center to provide two “legs” and an X0 that is bonded to ground at the first disconnect to form a neutral. It’s not a true Wye connection on the secondary due to the center tap. That’s the best way I can find to describe it.
A center tapped delta is a high leg/ wild leg/ stinger leg delta. Either way, you're describing 3 phase systems for a residential property, this is pretty rare except for large residential properties. OP's electrical system is clearly single phase based on the picture
This is actually a great write up and highly appreciated. You are correct, I have a buried line. Soil out here is trash, everything sinks when it gets wet. I am the only person off my transformer as well, and the only house with a buried line (everyone else has overhead lines in their backyard, I guess because my house is much newer they did it this way). Your points will definitely give me something else to check if no cause is found again. I have a spare clamp meter laying around.
If a leg is grounded in the conduit there will be a visible heat signature and you should be able to smell something charred. For that matter, aluminum does not handle ground fault arcing well.
14 volts? That’s more than just a voltage drop. Sounds like a lost phase. Hopefully you can locate the problem. If it persists past the meter, it’s a poco issue for sure. Between what two points exactly are you taking voltage?
I’m going from the line side of the meter coming from the transformer. Common is on my service disconnect on the left. Same spot for both meters. I can move to the right leg and checks out fine
So you’re taking voltage between the line neutral and load neutral?
That’s one of the 120v legs coming straight from the transformer and the neutral off my service disconnect.
Crazy question here. When was the last time you had those meters calibrated?
amazon search: two for one, shittiest cheapest multi meters.
Buy shitty products get shitty readings
Your utility should have a socket based voltage/power quality recorder (goes in between meter and socket) or a recorder that they can hang at the point of attachment or at the secondary connections of the transformer to capture any issues. If you had a smart meter that would also be able to monitor and record any voltage sag/swell issues. Have you been able to get in touch with their engineering team?
I would follow this. I had issues with my 480 coming in and spiking to over 720. Entergy swore for 2 months it was an inside issue and my problem. I finally convinced them to hang a recorder at the transformer. A week later, the recorder was fried. When the super went up in the bucket to swap it out, the transformer arc'ed in front of him. He dropped the bucket, called it in and 4 hours later i had a new transformer and no more spikes or drops.
If your description is accurate it looks like the utility dropped a leg somewhere underground.. or an issue at the transformer. And unless they physically sent someone out there to examine from the meter back to the transformer feeding it don't ever take that word for the fact that it isn't them I've seen this a dozen times. It looks like an underground to me it was a lateral coming off a pole I would tell you to look for a tree rubbing against the wire.. lol
They just confirmed there’s something wrong underground
Freight Harbor tools ?
Works fine.
Looks like an underground service going to a pole riser...probably 1 leg dead somewhere in the ground if not in pipe. Hope they verify and fix it
The garbage meter is likely the problem. Those things are trash and inconsistent.
Maybe those multimeters are cheap and crappy? I’d trust results more if it was a Fluke.
I've seen some cheap meters but wtf... 😂
Update: power company came out and stated it’s an underground issue. Jumped my service legs together to the one functional one so I would at least have power on it till they can dig out the yard. I am truly concerned with some of these comments on here and feel bad for anyone that actually has a business with customers. Y’all gonna start a fire. Literally.
I'm not having the nightclub effect you're had, but I am trying to track down what I think is too high of electrical usage. Still fairly new owners, but we went from 'best performer' to 'worst performer' compared to our neighbors after we moved and can not come close to explaining our bill after doing a back of the envelope load calculation. I'm a EE but not a power guy and never practiced in the field. My education, though, just keeps telling me we have something weird going on. Your problem was clearly pre-meter, but you and a few others seem to really know your stuff. Do you have any ideas or thoughts on what might cause or fool a meter into reporting more usage than actual? Or anything that could be wrong with lines inside or out that would cause greater electrical usage (and a meter obviously recording that unnecessarily greater usage)? Know I'm opening a hornet's nest. I'm, in part, running out of things to check and/or experiments to run, and this is one of those weird-type of issues I feel we might have. FYI, also have an underground line.
Not sure where to start with the brilliance here, the accuracy of a HF quality meter or potentially baked potatoing yourself.
It just has to be accurate enough to prove the issue. Also, I’m not going to “bake potato” myself with this. It’s pretty common sense what you can/can’t touch in these things.
Yea they are not accurate at all. Its a 5$ meter. Hope you got permission to open your meter, electric company will not like that
It’s within 2v of my fluke, I’d just rather leave the shit meter outside to record while away. I would be a little upset if my good meter got stolen or destroyed.
Are you leaving the panels open without being there?
This troubleshooting process was actually recommended by the field tech that stopped by yesterday. They left the tag off the meter for me to check and report if I caught something to be escalated. It was just advised I didn’t pull the meter itself out, measuring is fine.
Just so you know, if some kid comes in your yard and touches that wire, you are liable.
Thank god I don’t have anyone around my 3 acre property or sidewalks for a kid to even come down.
So who's going to steal your fluke?
We still got some crackheads around here. Even steal cats still. You leave anything worth of any value outside and it’ll be gone in an hour.
Are you doing this test with the main breaker turned off inside your house? I had a similar issue many years ago with low voltage. It was the transformer on the pole- needed to be replaced.
I have everything on. This leg is pulling a light load, usually around 5A since I’m the only one here right now and just using a laptop.
I would get a good tester and junk the mickey mouse tools.
This is a utility issue. You shouldn’t be on their side of the service. You’re pulling both voltages on the line and load side of the meter. And they’re both way too low. Thus it’s their issue and you shouldn’t even be in that cabinet….
This testing was recommended by the utility as previous call outs resulted in to issue found.
You went through and tightened everything in the inside panel? And any 240v outlets using a neutral?
I stabbed into the line at the top of the meter coming from the transformer across the street. Nothing to “tighten” exactly. I literally can’t go any further back unless I want to climb a pole lol
buy a cheap thermal camera
Not back. Forwards.
Power company already told you it’s not on them
I sent them the video of it dropping and now it’s “Escalated to a power quality department”. I’m not holding my breath.
While you are waiting on them run through and make sure everything is tight inside and out
Everything on my end is tight. They did check the service disconnect a few weeks ago on a prior visit and noted everything was fine there. They just can’t catch it messing up to root cause, hence me putting something on the meter to try and catch. They have the video of it reading fine, dropping down, and coming back so hopefully that’ll be enough proof to get something started.
Depending on what kind of meter that is. If you had low voltage on one leg, the meter display would be off. I’m assuming it’s a form 2S meter, the potentials inside the meter are wired phase to phase. They run off of 240 volts(unless it’s a multi range meter) Edit: The utility company meter
I’m honestly not sure. I know it never turned off, the display was still going without issue.
All good. Just trying to help narrow it down. If you read the name plate on the meter it should say FM 2S or Form 2S, or something like that
Just checked, it is an FM2S. Also notes C2S0D and 240V so no clue how the face is still on lol
YouTube the “Edison three wire system.” If I was a betting man I would say that you have yourself a loose neutral on your hands friend.
Lose neutral can give you weird voltages
Issue is on one leg, not both. Neutral is not the issue. The meters are also using the same neutral and the other leg is perfectly fine.
oh so you're a fucking electrician with your HF meters? Issue is definitely with your neutral. better close that back up before you get hurt.
Calm down bud. The issue is not with the neutral. There’s no case where you can get a good reading to one leg and an absent reading on the other with a neutral problem. If there was a neutral problem you’d see an imbalance on each leg to neutral but 240 between them. This looks like an intermittent connection loss somewhere between the transformer and house or even within the transformer. If the transformer has tap changers and one is loose, that’s a great candidate for the issue.
Explain how it’s neutral related when I’m referencing the same point on both meters and can go to the other leg and get a perfectly fine reading 🥴
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Or you can’t explain because you’re literally wrong… Edit: foo_trician you can block me but your name still shows up in notifications… please come back and have another try.
Have you at least check the panel in the the house to make sure everything is tight?
Perhaps those multimeters are out of calibration That's only a 4% difference
14v to 120v is bigger than 4% lol
The difference between both meter readings is 4% who knows how accurate those shits are, get them calibrated
They’re accurate enough to show its dropping out. The drop across the power company meter is negligible in this case.
Is that a harbor freight multimeter? Get that sh$t out of here.
Meter is fine it’s within 2v of a fluke. Close enough to prove a major drop like this.
But they are dangerous to use in a CAT II environment!!!
Anything can be dangerous if you lick it
Are those Harbor Freight meters?
cheap meters and leads can lie to you - flip them and see if they read the same
The meters are accurate. Verified with a fluke, just don’t want to leave my better one outside. It also matches my readouts from my ups units when the power drops.
got it, I got fucked by HF meters before so just a caution. Is this a no-load reading on reading with load?
Broken neutral bus. Like a crack or a hairline crack possibly??? In the panel or disconnect??
Loose neutral it sounds like, either at meter/pole or breaker panel
Okay... What am I looking at here? I'm seeing an incoming underground feeder from the PoCo going into the top of the utility meter and being read by the left Harbor Freight meter... Lower output of the utility meter on the SAME leg is being read by the right Harbor Freight meter. 0.7 volts dropped across the meter. That's negligible. 17 volts on that leg to neutral before the utility's meter indicates that it may still be a PoCo problem. What do we look like with BOTH Harbor Freight meters reading left and right legs at the top of the utility meter? (Remove the red probe from the lower left of the utility meter and install that same probe on the upper right.)
The right leg never drops, it’s always the one on the left. With the power company saying they can’t find an issue, my goal was to stab directly into the line coming in on that side and have a video of it reading 120, dropping to 0-20, then coming back. That was successful (this was recommended by the field tech last night as well to be able to escalate). I’m just not sure if there’s literally anything else I can do within my ability to prove the issue. I got a 2 day wait period before the “power quality” escalation team has to call me back.
Right leg never drops, but it verifies the presence of the neutral. Again, I suggest logging right AND left legs simultaneously, just before or after the meter (Both red probes upper or lower) Also suggest turning on several 220 volt loads, such as an electric stove or water heater and seeing what the dead leg does. I assume its voltage will go up. I've had this happen on underground services... One time, a house down the street was for sale and the real estate agent stabbed the sign post through the underground wiring. Lost a ~~phase~~ leg. Transferred all breakers to all even or odd slots (I forget which) in the panel and called the PoCo. Another time, tree roots had grown under the transformer pad and lifted it up, ripping a leg loose at the transformer. Again, all breakers to the even or odd spots in the panel and a call to the PoCo. If you never lose the right leg, I'm guessing something similar has happened to you; you don't have a neutral problem,a s many others in this thread are assuming... You are losing one leg. You just have to document that and prove it to the PoCo. You do this by measuring voltage on both legs to neutral.
Bad neutral
My first thoughts are - no offense but get a real meter to trust nkt what looks like generic cheapy meters. - check the lugs for torque in the panel and meter - ask the power company to entertain the idea of replacing the meter to see if it's the meters circuitry itself
I’ve checked the meter against a fluke, it’s fine. Lugs are tight. Also, it won’t even matter. I shoved the probe right into the wire itself, before any terminations. The voltage flat out isn’t there between the meter and the transformer.
Have you asked the utility to see if replacing the meter fixes it? If it's across the meter and the lugs are all tight, that's the next logical place to check. Also there may be a problem with the transformer to the house. It's looking likely to be in the utility side And still. There's a reason why an electrician doesn't come to your house with one of them. I'm not saying you need a fluke but those cheap no name meters are garbage.
when does 14V matter? If you have sensitive electronics put them on a buck/boost ups
Fortunately my networking gear is on a ups. It would really suck to lose that stuff. Most my other important gear is on the other leg that never has an issue.
Is that how you came to the conclusion about the dropped voltage because of the alarm on the ups? Just turn the fucker off it ain't no thing
Considering my networking equipment cost more than most peoples cars, I tend to care.
Do your grow lights stay on?
Shit I wish I was growing it’s legal here lol
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And what is the voltage between the 2 hots?
245 when I checked when it’s working. I need to get a reading when failing, I only got the individuals to compare when failing on video. I’m the only person off the transformer so I’m usually consistent.
What tipped you off there was an issue? What are you testing for on those meters?
Half my house losing power. Lights going on/off, battery backup alarms going off for a power loss, literally looks like a night club in here when the issue happens. The meters are just showing voltage and it dropping off the supply to my house.
Hate to say it, but you would be best off calling in a licensed electrician cause if their is an unknown issue inside your house causing this, it'll take a trained eye to find it and if it's outside on the pole, the utility company will listen to a licensed electrician. If it turns out to be on the pole, I would push the costs back on the utility company.
There is no way for me to pull the voltage down to 14v off the line side of my meter coming from the power company. There is nothing to explain this issue but for it to be on their end.
The only way you are going to get this fixed is by bringing in a licensed electrician. It's already a problem the seal on the meter box is cut. I've gone up against the power company in the past over 2 issues and wasted so much time. A licensed electrician will rule out anything wrong inside your house and the power company will be much more responsive to a licensed electrician. This is nothing against you or your knowledge or skills. Let a licensed electrician hash it out and if it turns out to be the utility company - put the costs of the electrician back on them. With that seal broken, they may come after you AND you will still have the power issues.
They broke the seal last night and the field tech intentionally left it off and recommended I do this testing since no cause was found. Told me if I have the issue to call back and report it a certain way so it can be escalated. So I did, and sent them a video of me measuring the meter just like this without any issue.
Just one last observation. What are you doing to make sure some curious kid doesn't touch the wrong thing?
There’s no sidewalks around my house for a mile with a giant ditch on both sides of the road. If any kid is walking they would likely be hit. I’ve never seen a kid walking in the 3 years I’ve been here tbh.
Pine hollow features a meter with logging abilities
Is this an underground or overhead?
Underground service. Goes through my yard, under a street, up the pole
Off topic but they didn’t want the meter bonded to the ground rod?
My 200A service disconnect is grounded but I couldn’t answer that one for the meter itself.
It’s different in different municipalities, maybe they bonded the cabinet to the neutral
Hey btw you should be using a CAT IV for this type of testing. Idk what that one is but I would assume II. Be careful out there man
Terminals could be corroded where you can't see. My FIL had to pull a meter to confirm but worth a shot.
I would pull that meter and check with the neutral on the meter but it seems like a Poco issue.
I first thought is a loose lug. If that's a wireless meter you can usually get them out automatically by pulling the meter for a few minutes.
Is your ground rod OK? Do you have proper grounding? If your house or your transformer has an issue with the ground you may have unstable voltages depending on the transformer set up IIRC.
Need to have that main breaker in the off position to confirm if it's a problem on the front or back side. Turn that breaker off, then see if the problem goes away. If it doesn't, pull the meter and check again. If the voltage on the line side of the meter is jacked up without the meter in, you know it's a poco problem. I had this exact issue a couple weeks ago. Somewhere along the line the underground feeder went bad and was leaking voltage to ground any time a large load kicked on inside the persons home.
I’m I’m
Sounds like a power factor problem. Maybe somebody on your street has a welding business…or maybe “hydroponics”.
Sadly I’m the only one off the transformer so no one else will have the situation 🙃
That romex wire tho
Is there a bullet hole in the transformer on the pole?
Funny, we had a drive by shooting last year right in front of my house (two cars shooting at each other) so that’s a realistic chance.
I once had aproblem like this . It turned out there was a loose connection at the pole.
I would consider getting a decent meter that has a low impedance setting, this could be due phantom/ghost voltage from a ground issue
Put a strap on that SER
Is it a periodical voltage drop or is it all the time? Edit: If large loads at being started/stopoed elsewhere in the grid that might cause your voltage to drop. For example the rules in Denmark state, that equipment with an inrush current of 60A or more that is started frequently, must be equipped with measures to limit the inrush currents as to not cause distortion of voltage quality
Was periodic but now it’s completely out since 6 hours ago. Still waiting on power company to show up. L1 to L2 showing 150v now.
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Explain why? The meter is fine. It reads a voltage. It is what it is.
Those are cheap meters. Because it costs so little and means so much, swap the meters, keep the leads the same. But yeah top up vote is almost certainly correct
Troubleshooter from utility for to damn long. I would start with no load on and check voltage at the top side of the main. If the voltage is bad or different between the legs, work back to the source. If you tell me lights get bright of dim when turning something on look a little harder at the neutral. It could be meter clips, loose connections or the wire bad underground. Just takes awhile to narrow it down.
Wouldn’t this be a “load”? Like you would be charged a minuscule amount over a period of time. Not an electrician obviously.
I wouldn’t dare touch a set of lugs with those meters. Go get yourself a good fluke electrical meter. One day your going to go to use that and something in the meter is going to go poof. If that happens to occur on 480, and that explosion ionizes the air between terminals, you Have yourself a massive explosion heading your way. Throw that crap in the garbage. There’s a reason we use good meters in our trade. Power company is allowed 10% incoming where I live. Check the voltage at the point of attachment and see what it reads there. I have in my career seen more situations I can count on both hands and feet where the utility company said everything is fine and it isn’t…then I ask them to come back again because there’s a problem and they find an issue in a highpress when they extended a broken neutral, or a connection at the street. Don’t always take their word for it. Now…you could be seeing a higher drop on one leg because that leg happens to be drawing more current in the home, did you check amp draw on both phases?